Three typical agricultural planting areas in riparian plain of Jiangyin City

i.e.，greenhouse vineintensive planting base，vegetable intensive planting base

and general planting farmland

were selected as research objects and dynamic changes of soil nitrate nitrogen content under different planting patterns were studied by the experimental method of field sampling analysis. Results indicated that the variation of nitrate nitrogen content in vine planting base fluctuated greatly with time. However

the variation amplitude of nitrate nitrogen content in surface soil was greater than that in deep soil layer in vegetable intensive planting base and general planting farmland. Nitrate nitrogen content in three typical planting areas showed a decreased tendency with the depth of soil profile

including the maximum of soil nitrate nitrogen content appearing in the 20-40 cm layer in vine planting base. The average accumulation of nitrate nitrogen in every soil layer in vine planting base was higher than that in vegetable intensive planting base and general planting farmland. The average accumulation of nitrate nitrogen in the 0-100 cm soil layer in greenhouse vine intensive planting base was up to 400.96 kg/ hm2

which was significantly higher than that in vegetable intensive planting base and general planting farmland. This indicated that unreasonable excessive fertilization let to nitrate nitrogen accumulation in the soil profile and increased the risk of nitrogen leaching loss and groundwater environmental pollution.